What is the immediate treatment for Hyperglycemic Hyperosmolar Nonketotic Coma (HHNK)?

Immediate Treatment for Hyperglycemic Hyperosmolar Nonketotic Coma (HHNK)

The immediate treatment for Hyperglycemic Hyperosmolar Nonketotic Coma (HHNK) should begin with aggressive isotonic saline administration at 15-20 ml/kg/h during the first hour to restore circulatory volume and tissue perfusion, followed by insulin therapy once hypokalemia is excluded. 1

Initial Fluid Resuscitation

• Begin with isotonic (0.9%) saline at 15-20 ml/kg/h during the first hour to restore circulatory volume and tissue perfusion 1
• Total body water deficit in HHNK is typically 9 liters (approximately 100-200 ml/kg) 1
• Fluid replacement should correct estimated deficits within the first 24 hours, with induced change in serum osmolality not exceeding 3 mOsm/kg/h 1
• After initial stabilization with isotonic saline, consider switching to hypotonic (0.45%) saline as losses of water typically exceed those of sodium 2

Insulin Therapy

• Once hypokalemia is excluded, administer an intravenous bolus of regular insulin at 0.15 U/kg body weight, followed by a continuous infusion at 0.1 U/kg/h 1
• If plasma glucose does not fall by 50 mg/dl from initial value in the first hour, double the insulin infusion every hour until a steady glucose decline between 50-75 mg/h is achieved 1
• When blood glucose reaches 250-300 mg/dL, add dextrose to the hydrating solution while continuing insulin infusion at a reduced rate 1
• Continue insulin infusion until mental status improves and hyperosmolarity resolves 1

Electrolyte Management

• Total body deficits in HHNK typically include sodium, potassium, chloride, and phosphate 1
• Once renal function is assured and serum potassium is known, add 20-40 mEq/l potassium to the infusion 1
• Monitor potassium levels closely as insulin therapy will drive potassium into cells, potentially worsening hypokalemia 3
• Consider phosphate replacement (20-30 mEq/L potassium phosphate) in patients with cardiac dysfunction, anemia, respiratory depression, or serum phosphate <1.0 mg/dL 1

Monitoring During Treatment

• Blood should be drawn every 2-4 hours for determination of serum electrolytes, glucose, blood urea nitrogen, creatinine, and osmolality 1
• Monitor fluid input/output, hemodynamic parameters, and clinical examination to assess progress with fluid replacement 1
• Watch for signs of cerebral edema, particularly in younger patients, as this is a serious complication of rapid osmolality correction 1, 4

Special Considerations

• Bicarbonate administration is generally not recommended as it does not improve outcomes 5
• For successful transition from intravenous to subcutaneous insulin, administer basal insulin 2-4 hours before stopping the intravenous insulin to prevent rebound hyperglycemia 5, 1
• Identify and treat any precipitating causes such as infection, myocardial infarction, or stroke 5, 1

Potential Complications to Monitor

• Hypoglycemia may occur with overzealous insulin treatment 3
• Hypokalemia can develop due to insulin-stimulated potassium movement into cells 3
• Cerebral edema is a risk, especially with rapid correction of hyperosmolarity 1, 4
• Hyperchloremic metabolic acidosis may result from excessive saline administration 1

Treatment Algorithm

1. Begin isotonic saline at 15-20 ml/kg/h for the first hour 1
2. Check serum potassium and renal function 1
3. Start insulin therapy: 0.15 U/kg IV bolus followed by 0.1 U/kg/h continuous infusion 1
4. Adjust fluid type (switch to 0.45% saline) after initial stabilization 2
5. Add potassium (20-40 mEq/L) once renal function is assured and serum potassium is known 1
6. When glucose reaches 250-300 mg/dL, add dextrose while continuing reduced insulin infusion 1
7. Monitor electrolytes, glucose, and osmolality every 2-4 hours 1
8. Continue treatment until mental status improves and hyperosmolarity resolves 1